南开大学李福军团队报道了可见光锂氧电池内部电场和界面键合工程的阶梯结。相关研究成果发表在2022年1月11日出版的国际知名学术期刊《德国应用化学》。

近年来，锂氧电池引起了人们极大的兴趣，但它们受到高动能势垒和阴极过电压的阻碍限制。

该文中，研究人员设计了一种在碳氮化物（Fe₂O₃/C₃N₄）上与赤铁矿连接的阶梯结构（S结构）作为双功能催化剂，以促进涉及可见光的锂氧电池的氧氧化还原。异质结中的内部电场和界面Fe-N键促进了光载流子的分离和定向迁移，建立了空间隔离的氧化还原中心，在该中心，C₃N₄上的光电子和Fe₂O₃上的空穴显著加速了放电和充电动力学。

这使得含有Fe₂O₃/C₃N₄的锂氧电池在光照下的放电电压升高3.13 V，高于在黑暗中的平衡电位2.96 V，充电电压为3.19 V，并且具有优异的倍率能力和循环稳定性。

研究工作将有助于金属氧电池阴极的合理设计。

附：英文原文

Title: Internal Electric Field and Interfacial Bonding Engineered Step-Scheme Junction for Visible Light-Involved Lithium-Oxygen Battery

Author: Zhuo Zhu, Qingliang Lv, Youxuan Ni, Suning Gao, Jiarun Geng, Jing Liang, Fujun Li

Issue&Volume: 2022-01-11

Abstract: Li-O2 batteries have aroused considerable interests in recent years, however they are hindered by high kinetic barriers and large overvoltages at cathodes. Herein, a step-scheme (S-scheme) junction with hematite on carbon nitride (Fe2O3/C3N4) is designed as a bifunctional catalyst to facilitate oxygen redox for visible light-involved Li-O2 battery. The internal electric field and interfacial Fe-N bonding in the heterojunction boost the separation and directional migration of photo-carriers to establish spatially isolated redox centers, at which the photoelectrons on C3N4 and holes on Fe2O3 remarkably accelerate the discharge and charge kinetics. These enable the Li-O2 battery with Fe2O3/C3N4 to present an elevated discharge voltage of 3.13 V under illumination, higher than the equilibrium potential 2.96 V in dark, and a charge voltage of 3.19 V, as well as superior rate capability and cycling stability. This work will shed light on rational cathode design for metal-O2 batteries.

DOI: 10.1002/anie.202116699

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202116699